2,951 research outputs found

    Classifying word problems of finitely generated algebras via computable reducibility

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    We contribute to a recent research program which aims at revisiting the study of the complexity of word problems, a major area of research in combinatorial algebra, through the lens of the theory of computably enumerable equivalence relations (ceers), which has considerably grown in recent times. To pursue our analysis, we rely on the most popular way of assessing the complexity of ceers, that is via computable reducibility on equivalence relations, and its corresponding degree structure (the c-degrees). On the negative side, building on previous work of Kasymov and Khoussainov, we individuate a collection of c-degrees of ceers which cannot be realized by the word problem of any finitely generated algebra of finite type. On the positive side, we show that word problems of finitely generated semigroups realize a collection of c-degrees which embeds rich structures and is large in several reasonable ways

    The Causes and Consequences of Corruption: A Review of Recent Empirical Contributions

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    Summary This article presents a review of recent developments in the empirical literature on corruption which uses subjective indices and survey data. The results are presented on two broad themes: contributions to understanding the causes of corruption and theories on the consequences of corruption. Though this type of research is still in its infancy, it has already provided the field of corruption with some of the empirical discipline needed to turn its fertile theorizing into policy recommendations

    Predictable phenotypic, but not karyotypic, evolution of populations with contrasting initial history

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    This study was financed by Portuguese National Funds through FCT - ‘Fundação para a Ciência e Tecnologia’ within the projects PTDC/BIA-BEC/098213/2008, PTDC/BIA-BIC/2165/2012 and cE3c Unit FCT funding UID/BIA/00329/2013. I.F. had a PhD grant (SFRH/BD/60734/2009), P.S. has a Post Doc grant (SFRH/BPD/86186/2012) and S.G.S. has a Post Doc grant (SFRH/BPD/108413/2015) from FCT. M.S. is funded by grant CGL2013-42432-P from the Ministerio de Economía y Competitividad (Spain) and grant 2014 SGR 1346 from Generalitat de Catalunya. The datasets generated during and/or analysed during the current study are available in the figshare repository, at https://doi.org/10.6084/m9.figshare.4797550.The relative impact of selection, chance and history will determine the predictability of evolution. There is a lack of empirical research on this subject, particularly in sexual organisms. Here we use experimental evolution to test the predictability of evolution. We analyse the real-time evolution of Drosophila subobscura populations derived from contrasting European latitudes placed in a novel laboratory environment. Each natural population was sampled twice within a three-year interval. We study evolutionary responses at both phenotypic (life-history, morphological and physiological traits) and karyotypic levels for around 30 generations of laboratory culture. Our results show (1) repeatable historical effects between years in the initial state, at both phenotypic and karyotypic levels; (2) predictable phenotypic evolution with general convergence except for body size; and (3) unpredictable karyotypic evolution. We conclude that the predictability of evolution is contingent on the trait and level of organization, highlighting the importance of studying multiple biological levels with respect to evolutionary patterns.Publisher PDFPeer reviewe

    How phenotypic convergence arises in experimental evolution

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    Evolutionary convergence is a core issue in the study of adaptive evolution, as well as a highly debated topic at present. Few studies have analyzed this issue using a "real-time" or evolutionary trajectory approach. Do populations that are initially differentiated converge to a similar adaptive state when experiencing a common novel environment? Drosophila subobscura populations founded from different locations and years showed initial differences and variation in evolutionary rates in several traits during short-term (∼20 generations) laboratory adaptation. Here, we extend that analysis to 40 more generations to analyze (1) how differences in evolutionary dynamics among populations change between shorter and longer time spans, and (2) whether evolutionary convergence occurs after 60 generations of evolution in a common environment. We found substantial variation in longer term evolutionary trajectories and differences between short- and longer term evolutionary dynamics. Although we observed pervasive patterns of convergence toward the character values of long-established populations, populations still remain differentiated for several traits at the final generations analyzed. This pattern might involve transient divergence, as we report in some cases, indicating that more generations should lead to final convergence. These findings highlight the importance of longer term studies for understanding convergent evolution.info:eu-repo/semantics/publishedVersio

    Evaluation of Progesterone Agent Utilization and Birth Outcomes in a State Medicaid Plan

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    An analysis of medication adherence and birth outcomes among members receiving progesterone for the prevention of preterm birth in a state Medicaid program. Data is also used to evaluate the association between member characteristics and medication adherence and birth outcomes as well as whether there was a change in the cost of care

    The Prevalence of Urogenital Infections in Pregnant Women Experiencing Preterm and Full-Term Labor

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    Urogenital infections are extremely prevalent during pregnancy and are an important cause of premature labor. However, the prevalence of urogenital infections during childbirth is not well known. Objective. Identify urogenital infections present at the beginning of labor in both full-term and preterm pregnancies. Study Design. Ninety-four women were admitted to the inpatient maternity clinic of the Federal University of Rio Grande do Norte (UFRN). In total, 49 women in preterm labor and 45 women in full-term labor were included in the study, and samples of urinary, vaginal, and perianal material were collected for microbiological analysis. Results. The prevalences of general infections in the preterm labor group and the full-term labor group were 49.0% and 53.3% (P = 0.8300), respectively. Urogenital infections in the preterm and full-term labor groups included urinary tract infection in 36.7% and 22.2% of women, vaginal candidiasis in 20.4% and 28.9% of women, bacterial vaginosis in 34.7% and 28.9% of women, and group B streptococcus in 6.1% and 15.6% of women, respectively. Conclusions. Urogenital infections were prevalent in women in preterm labor and full-term labor; however, significant differences between the groups were not observed

    Laboratory Selection Quickly Erases Historical Differentiation

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    The roles of history, chance and selection have long been debated in evolutionary biology. Though uniform selection is expected to lead to convergent evolution between populations, contrasting histories and chance events might prevent them from attaining the same adaptive state, rendering evolution somewhat unpredictable. The predictability of evolution has been supported by several studies documenting repeatable adaptive radiations and convergence in both nature and laboratory. However, other studies suggest divergence among populations adapting to the same environment. Despite the relevance of this issue, empirical data is lacking for real-time adaptation of sexual populations with deeply divergent histories and ample standing genetic variation across fitness-related traits. Here we analyse the real-time evolutionary dynamics of Drosophila subobscura populations, previously differentiated along the European cline, when colonizing a new common environment. By analysing several life-history, physiological and morphological traits, we show that populations quickly converge to the same adaptive state through different evolutionary paths. In contrast with other studies, all analysed traits fully converged regardless of their association with fitness. Selection was able to erase the signature of history in highly differentiated populations after just a short number of generations, leading to consistent patterns of convergent evolution

    Genital ulcers in women: clinical, microbiologic and histopathologic characteristics

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    Female genital ulcer is a disease that affects a large number of women, and its etiologic diagnosis can be difficult. The disease may increase the risk of acquiring HIV. Genital ulcer may be present in sexually transmitted diseases (STD) - syphilis, chancroid, genital herpes, donovanosis, lymphogranuloma venereum and other non-STD disorders (NSTD) - Behçet's syndrome, pemphigus, Crohn's disease, erosive lichen planus and others. This study evaluated the clinical-histopathologic-microbiologic characteristics of female genital ulcers. A cross-sectional descriptive prospective study was conducted during a six-month period to investigate the first 53 women without a definitive diagnosis, seeking medical care for genital ulcers at a genital infections outpatient facility in a university hospital. A detailed and specific history was taken, followed by a dermatologic and gynecologic examination. In addition to collecting material from the lesions for microbiologic study, a biopsy of the ulcer was performed for histopathologic investigation. The average age of the patients was 32.7 years, 56.6% had junior high school education and higher education. The most frequent etiology was herpetic lesion, followed by auto-immune ulcers. At the time of their first consultation, around 60% of the women were using inadequate medication that was inconsistent with the final diagnosis. Histologic diagnosis was conclusive in only 26.4% of the patients (14/53). Cure was obtained in 99% of the cases after proper therapy. The female genital ulcers studied were equally distributed between sexually transmitted and non-sexually transmitted causes. Herpes was the most frequent type of genital ulcer, affecting women indiscriminately, mostly between the ages of 20 and 40 years. The etiologic diagnosis of herpetic ulcers is difficult to make even when various diagnostic methods are applied. It is imperative that NSTD should be included in the differential diagnoses of female genital ulcers. The histopathologic exam is not a diagnostic tool in the majority of cases and should not be considered the gold standard test, being of little value in cases of NSTD and STD ulcers.25426
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